/Engine/Plugins/Editor/ObjectMixer/ObjectMixer/Source/ObjectMixer/Public/Views/List/Modes/ObjectMixerOutlinerMode.h
Called by the outliner when an item passes filters but isn't yet added to the tree
virtual void OnItemPassesFilters ( const [ISceneOutlinerTreeItem](API\Editor\SceneOutliner\ISceneOutlinerTreeItem) & Item )